Cheetah keyboard 770

[catosalsa]

Have a Cheetah master series 770 keyboard. A battery were leaked on the pcb and had to put few jumpers in were traces were damaged. After a board cleaning and the jumpers in the keyboard starts and display working properly (it didnt start at all before). Tested it with a Roland sound canvas and i workes exept for a few keys in the area marked in the attached pic. They work when playing all of them at the same time. But one at a time no sound or with a long delay before the tone. Sometime sound like a short arpeggio or something.

any suggestions why only these few notes sounds like this, nothing else?

 

[catosalsa]

 

[catosalsa]

 

[abbey road d enfer]

Keys are multiplexed. The problrm is likely to be excessive resistance in the address line corresponding to this group of notes. A schematic would help.

 

[catosalsa]

Keys are multiplexed. The problrm is likely to be excessive resistance in the address line corresponding to this group of notes. A schematic would help.

Thanks! Haven’t found a schematic yet. Will look again!

 

[catosalsa]

Keys are multiplexed. The problrm is likely to be excessive resistance in the address line corresponding to this group of notes. A schematic would help.

Seems impossible to find the schematic